$fn=100;

rotate_extrude(){
    difference(){
        union(){
            translate([10.5,0,0]) square([5,7],center=true);
            translate([19.5,0,0])square([5,7],center=true);
        }
        translate([14.75,0,0])circle(3.5);
    }
}

for(ball=[0:30:360]){
    rotate([0,0,ball])
    translate([14.75,0,0])
    sphere(3.25);
}

        